The present invention is directed to fuel vaporizer devices for vaporizing liquid fuel supplied to an internal combustion engine, and more specifically to a method and apparatus for efficiently vaporizing liquid hydrocarbon fuel in a closed system prior to its entry into an internal combustion engine""s combustion chambers in amounts proportional to the acceleration level of the engine, thereby increasing the engine""s fuel efficiency and decreasing the engine""s emissions of pollutants to the environment.
In an internal combustion engine, combustion of a fuel takes place in a confined space, producing expanding gases that are used directly to provide mechanical power. In the confined space, or combustion chamber, a portion of the liquid hydrocarbon fuel is converted to a gas because of the partial vacuum formed therein during the intake portion of the engine""s cycle of operation. During the following compression portion of the engine""s cycle, the compression of the gases (in diesel engines) and/or the heat of a spark (as in gasoline engines) functions to ignite the gaseous portion of the fuel. The resulting expansion of gases during the power portion of an engine""s cycle forces movement of a piston and resulting conversion of chemical to mechanical energy.
The fuel must be in a gaseous state to combust. This is true whether the fuel is gasoline, diesel, liquid petroleum, wax, wood or any other combustible material. This is why the liquid fuel used in an internal combustion engine is first converted to its gaseous state before being combusted under the pressure of compression and/or by the heat of a spark.
Unfortunately, the internal combustion engine currently accomplishes this task inefficiently by the partial vacuum created in the combustion chamber (or cylinder) during the intake portion of an engine""s cycle. In that partial vacuum, liquid fuel and air is drawn into the cylinder where a portion of the liquid fuel is vaporized because of the vacuum and thus combustible when exposed to the heat of a spark or under compression. Unfortunately, less than 40% of the liquid fuel is typically vaporized in this process and combusted to provide power and heat. Most of the remaining liquid fuel is converted to vapor after the initial combustion, too late to be converted to mechanical power and heat, and is instead released to the environment during the exhaust phase of the cycle as a pollutant. Some 60% or more of the liquid fuel entering the combustion chamber is, therefore, wasted and exhausted to the environment.
Numerous attempts have been made in the prior art to more completely vaporize the liquid fuel supplied to internal combustion engines in order to improve their performance and/or efficiency, or to reduce the pollutants discharged into the atmosphere with the exhaust from the engine. The higher the proportion of fuel entering an engine""s cylinder as vapor rather than liquid, the higher the proportion of fuel combusted and the less fuel required to achieve the same amount of mechanical energy. Given the ever increasing costs of fossil fuels and the unreliability of foreign sources, it is understandable that much effort would be expended to increase energy efficiency to conserve energy as well as decrease pollution.
Several U.S. patents were found that attempt to increase the proportion of fuel entering the combustion chambers as a gas to improve an engine""s efficiency and limit the amount of fuel emitted as pollutants. They each fail to achieve this goal adequately, however, for reasons noted below.
U.S. Pat. No. 4,350,134, to Sparks, relates to a method and apparatus for producing an air/fuel vapor mixture for use in the combustion chambers of an internal combustion engine. The apparatus includes an enclosure into which ambient air is introduced with a heater for heating the ambient air together with a fuel vaporizer for vaporizing fuel injected into the enclosure and for mixing with the heated air and another heater for heating the resulting air/fuel vapor mixture which is subsequently conducted out of the enclosure to the combustion chambers of the internal combustion engine. The invention fails to provide means by which the amount of fuel entering the vaporization device is regulated to match the engine""s precise requirements at any given time.
U.S. Pat. No. 4,538,583, to Earl, and its Continuation-in-Part U.S. Pat. No. 4,622,944, relate to a system for supplying fuel to an internal combustion engine that includes a two-stage evaporator serially mounted within the fuel supply system of the engine. This device provides no precise fuel control and may produce more fuel vapor than needed at low speeds and not enough at higher speeds. The device provides no idle control and no way to move the vehicle until the device heats the fuel to its vapor point. The device also may be hazardous in that it contains glow plugs that could potentially heat some of the fuel to its flash point and cause a fire.
U.S. Pat. No. 4,550,706, to Hoffman, relates to a fuel vaporizer comprising an air/fuel heating and mixing chamber which vaporizes liquid hydrocarbon fuel to a heated, dry vaporous state and mixes it with heated air for introduction of the mixture into a primary or main air stream for supply to the cylinders of the engine. This device contains design flaws, one involving the location of a float relative to nozzles that will result in little to no fuel flow in the device, and another that will result in a buildup of fuel at the device""s atomizer. Such a buildup of fuel could pose an explosion hazard if the vehicle is involved in an accident.
U.S. Pat. Nos. 4,665,879 and 4,622,944, to Earl, relates to a fuel evaporation apparatus which comprises a two-stage evaporator designed to receive fuel such as gasoline in a liquid form and to completely transform the liquid fuel into its vapor state so as to increase the efficiency of operation of the associated internal combustion engine. The main flaw in this device is its lack of a fuel flow control so that fuel flow can be regulated to match the vehicle""s speed. The device also could result in a buildup of fuel that would pose a danger of explosion in an accident.
U.S. Pat. No. 4,898,142, to Van Wechem, et al., relates to a combustion engine with fuel injection system, having at least one cylinder with an air inlet passage, into which passage opens a fuel spray valve which is connected to a fuel pipe with pump, the fuel pipe containing a heating element. The heating element of the device, however, does not heat the fuel sufficiently for vaporization.
U.S. Pat. No. 5,398,663, to Kulasinghe and Estate, relates to an internal combustion engine comprising a heated chamber with heating element in which liquid fuel is gasified. This device fails to incorporate a means by which fuel flow can be regulated to match the requirements of the engine at variable speeds.
U.S. Pat. No. 5,746,188, to Cooke, relates to an apparatus for heating and vaporizing a liquid hydrocarbon fuel supplied to an internal combustion engine that includes a housing having an inlet and outlet. The heating wire of this device will not provide enough heat to vaporize the fuel and will potentially short out. The fuel vapor that is formed in this device is not transported to the engine quickly enough to be responsive to changes in acceleration.
U.S. Pat. No. 5,778,860, to Garcia, relates to a system for partially vaporizing the fuel to a vehicle internal combustion engine comprising a set of fittings for passing the fuel from the fuel pump or injection pump through a vaporization chamber which is placed adjacent the engine to heat the fuel, partially vaporizing it. This device""s heat source will not heat the fuel adequately to vaporize it.
The present invention is directed to overcoming one or more of the problems as set forth above.
Brief Summary of the Invention
The fuel vaporizer of the present invention is interposed between an internal combustion engine""s fuel injection system and intake manifold. It functions to vaporize a substantial portion of the liquid fuel injected into it by the fuel injector, thereby dramatically increasing the proportion of fuel supplied to the combustion chambers of the engine as a gas rather than liquid. Since it is only in its gaseous form that the fuel is combusted, increasing the proportion of fuel in the combustion chamber as gas greatly increases the proportion combusted during the compression portion of an engine""s cycle. The invention thus achieves a substantial improvement in fuel economy with a coincident reduction in pollutants through nearly complete combustion of the fuel. The invention will thus achieve enormous energy savings with fuel-injected engines of all kinds (both old and new) by an elegantly simple, safe and efficient means.
Objects and Advantages
Accordingly, a method and apparatus for vaporizing fuel prior to its entry into the cylinders of a fuel-injected internal combustion engine is provided. Several objects and advantages of the present invention are to provide:
a) means by which fuel may be more efficiently combusted and converted to mechanical energy in an internal combustion engine, thereby significantly increasing a vehicle""s fuel efficiency and decreasing a vehicle""s emission of pollutants to the environment;
b) heating means by which fuel may be largely converted to its gaseous state prior to entry into an engine""s combustion chambers by first heating the fuel to its boiling point using heating means powered by the vehicle""s electrical power source;
c) means by which the vaporization of fuel is achieved safely without risk of fire by heating the fuel to boiling, but not to its flash point;
d) means by which the vaporization of fuel is achieved in a closed system, thereby preventing the emission of excess fuel vapor to the environment and providing for its storage for later use at engine startup;
e) means by which the amount of fuel being vaporized at any one moment is regulated and may be varied to meet the precise power output needs of the vehicle by use of the engine""s fuel injection system;
f) means by which engine start is assured in both warm and cold climates; and,
g) means by which the present invention may be easily adapted and tooled to fit most engines, including both old and new engines.
Further objects and advantages of the present invention will become apparent from a consideration of the drawings and ensuing description.